Make Godot maps in Trenchbroom or whatever else. There's a 3.x version available as well.
This is great. I've always enjoyed and preferred working with CSG brushes in Hammer Editor and JACK over using modeling software, especially as a programmer, so having this kind of native support for it is nice.
Godot is looking more and more attractive each time I read something about it. I'm still using Unity at the moment, but have been planning to look into Godot as soon as it would get first-party support for C# and .NET, which has happened by now I believe. I really despise Unity's direction and management, and the fact the engine is closed source. 
The only thing still holding me back is the fact I've invested so much in Unity, and find it daunting to see a lot of it go to waste. 
I've spent enough time with both engines to know that I only want to make games in Godot due to how it reduces Unity's Scene and Prefab concepts down to one Scene concept — Unity drawing a distinction between the two has always chafed.
Plugin for Godot to import Quake maps, Trenchbroom is a tool for making Quake maps that is still in use and has a pretty big community, this is pretty nice as Trenchbroom is a pretty good tool for making 'general retro maps'
